These past few weeks, we've been diving into our study of sound. In science we wondered whether it was possible to see sound. Students had varying hypotheses. Some who believed we might be able to see sound reasoned that if they could feel sound when they touch their throat while talking or feel a trembling in their bodies when loud music is played, that they might be able to see sound. After we finished discussing our hypotheses, the class divided into groups.
Each group stretched plastic wrap over a cup and then sprinkled a little salt on top of the plastic wrap. Students were then invited to speak next to the cups. We were amazed to see the salt jump as we talked. Students continued to experiment with the volume and pitch of their speech and observed that the louder they talked, the more the salt moved due to the vibrations. One group observed that the plastic wrap vibrated more when they spoke in a higher pitch voice.